Stable, effervescent vaginal suppositories

ABSTRACT

An effervescent vaginal suppository composition containing a stabilizer appropriately selected from the group consisting of anhydrous sodium sulfate, anhydrous silica gel, dried magnesium silicate, dried aluminum silicate, dried calcium carboxymethylcellulose, dried microcrystalline cellulose, dried starch and dried calcium phosphate or mixtures thereof, preferably in an amount of 0.1-20% based on the weight of said effervescent vaginal suppository composition. Shaped effervescent vaginal suppositories are produced therefrom.

This application is a continuation of now abandoned application Ser. No. 827,216, filed Feb. 5, 1986 which application is a continuation of now abandoned application Ser. No. 628,977, filed July 12, 1984, which application is, in turn, a continuation of now abandoned application Ser. No. 471,453, filed Mar. 2, 1983.

FIELD OF THE INVENTION

This invention relates to stable, effervescent vaginal suppository compositions and to the suppositories produced therefrom.

DESCRIPTION OF THE PRIOR ART

Effervescent vaginal suppositories have been previously disclosed to the public by Japanese Patent Publication No. 65814/1981 and Japanese Patent Application Laid-open No. 94415/1977. Such vaginal suppositories are those which incorporate a so-called effervescing agent and which generate a gas upon contact with the body fluid upon administration thereby exhibiting an effervescent phenomenon. Effervescing is required in the vagina mainly in such cases where a contraceptive effect is contemplated. Accordingly, this is a technique frequently employed in vaginal suppositories incorporating, for example, a spermatocide. There is also such a case where the effervescing properties are imparted for the purpose of enhancing the rapid disintegration properties of the vaginal suppository itself, but since making the suppository effervescent remarkably impairs the stability of the preparation, this is usually utilized where a contraceptive effect is contemplated. It is widely known that the effectiveness of such suppositories is great.

However, said preparation suffers from poor stability, and has the disadvantage that the neutralization reaction proceeds with time and hence the amount of effervescence is reduced at the time of administration or the packaged product becomes swollen due to the generated gas.

Under such circumstances, the present inventors have studied vaginal suppositories in an effort to eliminate the aforesaid disadvantage and stably maintain the effervescent properties. As a result, they have discovered that the above object may be achieved by incorporating into the suppository formulation the stabilizers described herein.

SUMMARY OF THE INVENTION

Accordingly, the object of this invention is to provide a composition for a vaginal suppository the effervescent properties of which remain stable over an extended period of time. In other words, this invention provides an effervescent vaginal suppository composition which contains one or more stabilizers selected from the group consisting of anhydrous sodium sulfate, anhydrous silica gel, dried magnesium silicate, dried aluminum silicate, dried calcium carboxymethylcellulose, dried microcrystalline cellulose, dried starch and dried calcium phosphate and mixtures thereof.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a figure showing results obtained in Effect Example 1; and

FIG. 2 is a figure showing results obtained in Effect Example 2.

DETAILED DESCRIPTION OF THE INVENTION

The base for the vaginal suppositories of this invention is not particularly restricted, but this is desirably water soluble in order that the neutralization reaction can rapidly proceed upon contact with the body fluid. Such bases are known in the art.

Therefore, for example, the use of polyethylene glycol as the base presents a preferred embodiment in this invention. Specific examples include mixtures of polyethylene glycols having molecular weights of 1,300-1,600, 950-1,050, 570-630 and 380-420 at appropriate ratios, for example, that containing 70-100% of polyethylene glycol having a molecular weight of 950-1,050 and 0-30% of polyethylene glycol having a molecular weight of 1,300-1,600 or that containing 20-40% of polyethylene glycol having a molecular weight of 1,300-1,600 and 60-80% of polyethylene glycol having a molecular weight of 570-630.

The effervescing agents employed are likewise known in the art.

There is no particular restriction on the effervescing agent which imparts the effervescent properties to the suppositories as long as it is a combination in which an inorganic acid, an organic acid or a water soluble alkali metal salt thereof is employed as an acidic substance and sodium bicarbonate or potassium bicarbonate is employed as a basic substance. It is preferred to employ phosphoric acid as the inorganic acid, or citric acid, tartaric acid, fumaric acid or malic acid as the organic acid. By the water soluble acid alkali metal salt is meant an acid alkali metal salt which is obtained by partially neutralizing a polybasic inorganic acid or a polybasic organic acid and which also is water soluble. Examples thereof include sodium dihydrogenphosphate, sodium dihydrogencitrate, and the like.

The stabilizer according to this invention, as illustrated in the Effect Examples and Examples described hereinbelow, may be appropriate selected from the group consisting of anhydrous sodium sulfate, anhydrous silica gel, dried magnesium silicate, dried aluminum silicate, dried calcium carboxymethylcellulose, dried microcrystalline cellulose, dried starch and dried calcium phosphate. The use of mixtures of two or more thereof is also envisaged in this invention.

While there is no particular restriction on the content of the stabilizer, a preferred range is 0.1-20% based on the weight of the vaginal suppository. Since the suppository itself becomes fragile if the content exceeds 20%, it is preferred that the content not exceed this upper limit.

As additional components in the vaginal suppositories, it is possible to add effervescing aids, such as amphoteric surfactants or ionic or nonionic surfactants, or egg white, gelatin and the like for maintaining the effervescence. As will be apparent, these are optional and do not restrict this invention.

The production of the suppositories of this invention may be practiced in conventional manner for producing said preparations, and, for example, it may be conducted as follows:

Firstly, a base, e.g., polyethylene glycol, is melted by heating. A stabilizer according to this invention is added, and the mixture is stirred to disperse the stabilizer therein. This mixture is then cooled to a temperature which is 10°-15° C. higher than its solidifying temperature and an effervescing agent is added to form a uniform dispersion. Further, an active agent, for example, a spermatocide, is added and the mixture is stirred to uniformly disperse or dissolve the agent therein. Then this mixture is injected into a mold cavity of a predetermined size and shape and cooled to form a suppository.

Since the suppositories of this invention are, as described above, often utilized in cases where a contraceptive effect is contemplated, it is a preferred embodiment to incorporate a spermatocide as an active agent. As the spermatocide, p-menthanylphenyl polyoxyethylene ether known under the trade name Menfegol is often employed. However, an antibacterial agent, such as tetracycline, an antiinflammatory agent, such as hydrocortisone acetate, or an antifungal agent such as chlordantoin, may be employed.

The effect of this invention is demonstrated by the Effect Examples described hereinbelow.

EFFECT EXAMPLE 1 Samples and Procedures

To a mixture of 60 mg of Menfegol, 5 mg of dioctyl sodium sulfosuccinate, 200 mg of potassium hydrogentartrate, 100 mg of sodium bicarbonate and 1,105 mg, 1,075 mg and 1,035 mg of a base comprising polyethylene glycols having molecular weights of 950-1,050 and 1,300-1,600 was added 30 mg, 60 mg or 100 mg of anhydrous sodium sulfate to prepare three different suppositories having a total weight of 1.5 g respectively. These were used as samples and stored at 37° C. for a month. The amount of the remaining sodium bicarbonate after storage was determined.

Results

The results are given in FIG. 1. From FIG. 1, it can be seen that anhydrous sodium sulfate exerts the stabilizing effect of this invention.

EFFECT EXAMPLE 2 Samples and Procedures

Four different vaginal suppositories were prepared by procedures similar to those described in Effect Example 1 except that the anhydrous sodium sulfate was employed in amounts of 10 mg, 50 mg, 100 mg and 200 mg respectively. These were used as samples and stored at 37° C. for a month, and the effervescing properties after storage were determined. The effervescing properties were determined by adding 3 ml of water at 37° C. and periodically measuring the effervescence volume.

Results

The results are given in FIG. 2. In FIG. 2, the curves depicted by the numerals 1, 2, 3 and 4 indicate the change in the effervescence volume with the time where the anhydrous sodium sulfate is added in amounts of 10 mg, 50 mg, 100 mg and 200 mg respectively. It can be seen from FIG. 2 that anhydrous sodium sulfate exerts the stabilizing effect of this invention.

EFFECT EXAMPLE 3 Samples and Procedures

Effervescent vaginal suppositories which were prepared by procedures similar to those described in Example 1 except that the anhydrous sodium sulfate was replaced by the stabilizers as set forth in the column of the stabilizer in Table 1 were used as samples and stored at 37° C. for a month. Thereafter, the change in the appearance (swelling of the package) and the maximum effervescence volume were examined.

Results

The results are given in Table 1.

                  TABLE 1                                                          ______________________________________                                                    Change in                                                                               Maximum Effervescence                                                 Appearance                                                                              Volume                                                                  after Storing                                                                             Immediately                                                                               After a                                                  at 37° C. for                                                                      after Pro- Month at                                    Stabilizer   a Month    duction    37° C.                               ______________________________________                                         Not added    Swollen    18.0 ml    13.50 m1                                    Dried magnesium                                                                silicate     No change  20.0 ml    21.85 ml                                    Dried aluminum                                                                 silicate     No change  19.4 ml    20.2 ml                                     Dried calcium car-                                                             boxymethylcellulose                                                                         No change  17.6 ml    17.4 ml                                     Dried microcrystal-                                                            line cellulose                                                                              No change  23.7 ml    23.0 ml                                     Dried calcium mono-                                                            hydrogenphosphate                                                                           No change  24.9 ml    22.0 ml                                     ______________________________________                                    

From Table 1, it can be seen that the effect of this invention is imparted by the stabilizers set forth in Table 1.

EFFECT EXAMPLE 4 Samples and Procedures

The effervescent vaginal suppository described in Example 3 (specimen) and a suppository obtained by excluding the anhydrous silica gel from said suppository (control) and the effervescent vaginal suppository described in Example 4 (specimen) and a suppository obtained by excluding the dried corn starch from said suppository (control) were used as samples and stored at 37° C. for a month. Thereafter, the change in the appearance (swelling) of the package) and the maximum effervescence volume were examined.

Results

The results are given in Table 2.

                  TABLE 2                                                          ______________________________________                                                           Maximum Effervescence                                                          Volume                                                               Change in Appearance                                                                           Immediately                                                                               After 1                                             after Storing at                                                                               after Pro- month at                                    Sample  37° C. for 1 month                                                                      duction    37° C.                               ______________________________________                                         Example 3                                                                      Control Swollen         24.5 ml    14.4 ml                                     Specimen                                                                               No Change       20.5 ml    19.0 ml                                     Example 4                                                                      Control Swollen         20.0 ml    13.5 ml                                     Specimen                                                                               No change       12.0 ml    12.8 ml                                     ______________________________________                                    

From Table 2, it can be seen that the effect of this invention is imparted by anhydrous silica gel and dried corn starch.

This invention is more particularly described by the following Examples.

EXAMPLE 1

80.0 g of polyethylene glycol (average molecular weight 950-1,050), 23.5 g of polyethylene glycol (average molecular weight 1,300-1,600), 6.0 g of Menfegol and 0.5 g of dioctyl sodium sulfosuccinate were melted together by heating to obtain a uniform mixture. To this mixture was added 5.0 g of anhydrous sodium sulfate and the mixture was stirred thoroughly to disperse. Then, 10.0 g of sodium bicarbonate, 25 g of potassium hydrogentartrate and 0.15 g of saponin were added successively, stirred and kneaded to uniformly disperse. The mixture was injected, while hot, into a mold having a predetermined shape and cooled to below room temperature. Thereby, an effervescent vaginal suppository having a spermatocidal effect and weighing 1.5 g per unit was obtained.

EXAMPLE 2

A spermatocidal effervescent vaginal suppository (3.0 g/unit) having the following composition was prepared by procedures similar to those described in Example 1.

    ______________________________________                                         Polyethylene glycol                                                            (molecular weight 1,300-1,600)                                                                       74.6      g                                              Polyethylene glycol                                                            (molecular weight 570-630)                                                                           111.9     g                                              Menfegol              6.0       g                                              Dioctyl sodium sulfosuccinate                                                                        0.5       g                                              Sodium bicarbonate    25        g                                              Monosodium fumarate   50        g                                              Anhydrous sodium sulfate                                                                             20        g                                              Egg white             12        g                                              ______________________________________                                    

EXAMPLE 3

An effervescent vaginal suppository (2 g/unit) having the following composition was prepared by procedures similar to those described in Example 1.

    ______________________________________                                         Polyethylene glycol                                                            (molecular weight 950-1,050)                                                                         116.6     g                                              Tetracycline          0.2       g                                              Dioctyl sodium sulfosuccinate                                                                        0.2       g                                              Sodium bicarbonate    20.0      g                                              Monopotassium dihydrogenphosphate                                                                    45.0      g                                              Anhydrous silica gel  10.0      g                                              Methylcellulose       8.0       g                                              ______________________________________                                    

EXAMPLE 4

An effervescent vaginal suppository (3.0 g/unit) having the following composition was prepared by procedures similar to those described in Example 1.

    ______________________________________                                         Polyethylene glycol                                                            (molecular weight 1,300-1,600)                                                                       68.8      g                                              Polyethylene glycol                                                            (molecular weight 950-1,050)                                                                         275.2     g                                              Hydrocortisone acetate                                                                               1         g                                              Sodium laurylsulfate  0.2       g                                              Sodium bicarbonate    20.0      g                                              Monosodium dihydrogencitrate                                                                         50.0      g                                              Dried corn starch     3.0       g                                              Polyvinylpyrrolidone  12.0      g                                              ______________________________________                                    

EXAMPLE 5

An effervescent vaginal suppository (2.5 g/unit) having the following composition was prepared by procedures similar to those described in Example 1.

    ______________________________________                                         Polyethylene glycol                                                            (molecular weight 950-1,050)                                                                         201.5     g                                              Chlordantoin          3.0       g                                              Dodecylaminoethylglycine (30%)                                                                       2.5       g                                              Potassium bicarbonate 8.0       g                                              Tartaric acid         10.0      g                                              Anhydrous sodium sulfate                                                                             25.0      g                                              ______________________________________                                     

What is claimed is:
 1. An effervescent vaginal suppository composition which consists essentially of:(A) from about 0.1 to about 20 percent, based upon the weight of the suppository composition, of anhydrous sodium sulfate as stabilizer, (B) an amount sufficient to achieve effervescence upon contact with vaginal body fluid of an effervescing agent which is a combination of:(1) at least one acidic substance selected from the group consisting of phosphoric acid, citric acid, tartaric acid, fumaric acid, malic acid and water soluble acid alkali metal salts thereof, and (2) at least one basic substance selected from the group consisting of sodium bicarbonate and potassium bicarbonate, the ratio of (1):(2) being sufficient to achieve effervescence of the composition upon contact with vaginal body fluid, (C) a base for vaginal suppository, and (D) an effective amount of a member selected from the group consisting of a spermatocide, an antibacterial agent, and antiinflammatory agent and an antifungal agent.
 2. An effervescent vaginal suppository composition according to claim 1 wherein the base for the composition is polyethylene glycol.
 3. An effervescent vaginal suppository composition according to claim 1 in the form of a suppository. 